Electric clutch coupling for use in dental technics



May 15, 1923.I

E. HUET TCH CGUPLING FOR USE IN DENTAL TECHNICS ELECTRIC CLU Filed Aug. 11 1921 m M V .A

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Patented May 15, 1923. 'i

vUNITED STATES PATENT lfFlCE.

EMILE HUET, F BRUSSELS, BELGIUM.

ELECTRIC CLUTCH COUPLING. FOR USE IN DENTAL TECHNICS. Application filed August 11, 192i. Serial No. 491,642.

To aZZwwm t may concern.' Fig. l is an axial section through the Be it known that I, EMILE HUET, a snbwhole device; ject of the King of Belgium, and resident Fig. 2 is a perspective view of the clutch of Brussels, Belgium, have invented certain member or steel block fixed to the mot new and useful Improvements in Electric shaft;

cai Clutch Cou lins for Use in Dental Tech- Fig. 3 is a ersnective view of the clutch .P c .I i

nies, of which the following is a specilicamember or block fixed to the nexible trans tion. mission shaft.

The small electric motors used at present l is the motor shaft, 2 is the end of the for driving the dental instruments or tools flexible transmission shaft carrying the tool. 05 Working the teeth preliminary to the sct- 3 is a tubular member provided with flanges ting of artificial teeth, bridgework and the upon which is wound a wire 4 forming the like, turn at a velocity of 7000 and even magnetizing coil. The ends 7, 7 of wire 10000 revolutions a minute, N ow it is nect are connected to the coils of the electric essary, in the dental practice, to stop the romotor and extend through corresponding 7o tary tool at any desired instant. A coupling bores of the sleeve or envelope provided device is therefore applied for connecting with a threaded flange G screwed on a corthe motor shaft with the flexible transmisn respondingly threaded end part of envelope sion shaft bearing the tool and this coupling 5. rlhe flange 6 is provided with a prodevice should be constructed and disposed jecting sleeve within which freely slidesin such a manner as to enable the transmis to a small amount the end of the lier-:ibie

sion shaft to stop when cutting off the elec transmission shaft.

tric current, whereas the motor shaft, owing 8 (Fig. 2) shows one of the clutch inemtoy the inertia of the rotary parts of the bers provided with a threaded hole (Fig. l)

motor, proceeds rotating for several revolufor being screwed on the correspondingly so tions before stopping. threaded end of the motor shaft, Chatel rlhe present invention relates to improif'emember 8 is provided with two sloped part ments in such clutch couplings formed of l0, l0 intended for engaging corresponding two cylindrical blocks of soft steel disposed parts ll, ll pro vided on the contiguous in front of each other and forming a clutch, face (Fig. 3) of the clutch member 9 which s' one of same being secured to the free end latter is secured to the end portion 2 of the of the motor shaft and the other to the corflexible transmission shaft. In an axial responding end of the flexible transmission bore of clutch member 9 is secured a sho-rt shaft, said clutches being inserted and opspindle l2 made of copper or brass and proerated in a known manner Within the central jecting from the clutch member. The pro- 9o hollow of a .magnetizing coil through which jecting portion of spindle l2 is slidably enflows a branch current derived from the gaged in a corresponding axial bore 13 of motor feeding current. It results that, clutch member 8, whereby both clutch meinwhen the current to the motor is cut off by bers are positively guided with respect to 4.0 the operator, no current flows through the each other. g5 magnetizing coil and the clutch coupling Vithin the bore 13 is engaged a short the shafts is disconnected by an interposed coil spring la which has for its object to coil spring, whereby both shafts are disconinstantaneously separate both clutch memnected from each other. bers 8 and 9 from each other when the cur- Now the characteristic feature of the rent is cut olf and to maintain same sepa- 100 present invention consists in arranging the rated during the time the current is cut oli". clutch in such a manner that, when the The working of the device may be readily operator cuts olf the current to the motor, understood. When the motor stops and the the transmission shaft, disconnected from current is cut ofi", spring let maintains both the motor shaft, instantaneously stops, clutch members 8 and 9 at a small distance 105 Whilst the motor shaft, owing to the inertia from each other; thc coupling is disconof its parts, still accomplishes several revonected. lVhcn electric current is admitted lutions before stopping. to the motor the motor shaft rotates; simul- The novel coupling device is shown in taneously the branch current flows through the accompanying drawing, in which: the coil 4, the steel blocks 8 and 9 become 110 `magnetizing coil 4, the clutches or vention, what the slidable block 9 is attracted magnets and the action towards the fixed block 8, against of the small coil spring 14, and the sloped parts or claws l() and 1l engage each other, whereby the transmission shaft, together with the tool fixed on it, turns in unison with the motor shaft.

lhen the operator cuts off the current to the motor, no current flows through the steel blocks 8 and 9 are (le-energized and pushed apart from each other by the action of coil spring H, whereby the clutch 9, fixed to he transmission shaft, stops instantaneously, the motor shaft still performing several revolutions.

Having now fully described my said in- I claim and desire to secure by Letters Patent, is:

1. An electrically operated clutch coupling for use in connection with electric motors operating dental tools, comprising a magnetizing coil fed by a branch current of the motor feeding current and axially disposed with respect to the motor shaft, and envelope for the magnetizing coil, a flexible transmission shaft, a rigid end portion on the latter shaft projecting through the envelope of the magnetizing coil and slidable within said envelope, a clutch member on the free end of the motor shaft, within the axial hollow of the magnetizing coil, a second clutch member fixed to the rigid end portion of the transmission shaft, in front of' the first named shaft, means for axially guiding the slidable Iclutch member in front of the fixed clutch member and means for automatically and instantaneously disconnecting the clutch members from each other after the electric current to the motor is out off.

2. An electrically operated clutch coupling for use in connection with electric motors operating dental tools, comprising a magnetizing coil fed by a branch current of the motor feeding current and axially disposed with respect to the motor sha t, an envelope for the magnetizing coil, a flexible transmission shaft, a rigid end portion .on the latter shaft projecting through the envelope of the magnetizing coil and slidable within said envelope, a clutch member on the free end of the motor shaft, within the axial hollow of the magnetizing coil, a. second clutch member fixed to the rigid end portion of the transmission shaft, in front of the first named shaft, sloped portions en the opposite free face of each of said clutch members, whereby said clutch members engage each other when the elecrie current passes through the coil, transfo-n'iing said clutch members into magnets, a short copper spindle on the second named clutch member, a corresponding axial bore in the first named clutch member, within which the said spindle is freely enga ed and guided when the corresponding clutc member slides axially and a short coil sprin made of copper located within said axia bore for instantaneously pushing both clutch members apart when the current to the motor is cut off.

3. ln a dental machine, the combination of an electric motor having a shaft, a flexible shaft having one end connected with a dental tool and the other end in alignment with the motor shaft, a solenoid having an axial bore disposed in axial alignment with the motor shaft and electrically connected for energization with the motor, a pair 0 clutch members mounted in the axial bore, one member being rigid on the motor shaft andL the other member mounted on the Hexible shaft, and means for normally disen gaging said members, whereby upon the operation of the motor the solenoid is energized for moving the clutch members into cooperative relation, and said means dsengages the members when the solenoid is cle-energized.

In testimony set my hand in whereof I have hereunto presence of two Witnesses. EMILE HUET.

lVitnesses (lnonons DeLnnnUoK, EMILE VoNwoMznLna. 

